Forming tube for glass fibers



Feb. 25, 1969 M CLEERY B. CUNNINGHAM ETAL 3,429,522

FORMING TUBE FOR GLASS FIBERS Filed Aug 15, 1965 Q INVENTORS: I MECLEEEY B.CUNNINGHAM P1 gr-Q 7-5 anczcHAkLEs KBUNLA JE.

ATTORNEY United States Patent 3,429,522 FORMING TUBE FOR GLASS FIBERS McCleery B. Cunningham and Charles K. Dunlap, Jr.,

Hartsville, S.C., assignors to Sonoco Products Company, Hartsville, S.C., a corporation of South Carolina Filed Aug. 13, 1965, Ser. No. 479,449 U.S. Cl. 242-11832 1 Claim Int. Cl. B65h 81/08; B31c 3/00 ABSTRACT OF THE DISCLOSURE A flexible spirally wound tube for winding glass fibers having at least one spirally wound paper inner ply and a spirally wound outer ply of resin impregnated, nonwoven textile material having a hard, uniformly smooth, slick outer surface.

This invention relates to glass fiber manufacturing and more particularly to a carrier or forming tube for use in the winding of freshly spun glass filaments or fibers.

In the spinning of glass fibers to be processed into textile material such as yarn and the like, glass in a molten condition is drawn through small openings or orifices in a plate commonly referred to as a spinneret into the form of continuous filaments which solidify upon contact with the air. These continuously drawn filaments are wound onto a tubular carrier in the form of a flexible cylindrical sleeve which is generally referred to as a forming tube. In a glass fiber spinning operation, this forming tube is slipped onto a spindle or the like which is rotated at very high speeds, frequently around 8,000 to 10,000 rpm. and up, and the glass filaments are drawn from the spinneret and wound on the tube at a relatively high linear speed generally 10,000 to 12,000 feet per minute and more. These forming tubes are used not only for such a winding operation but for subsequent winding and unwinding operations as well.

Due to the high speed at which the forming tube is rotated and the rugged conditions of use to which it is subjected, these tubes must meet rigid standards and preferably should be of a suitable design and material so as not only to be inexpensive in initial cost but to be capable of repeated use. Furthermore, these forming tubes must be provided with external surface characteristics specifically suitable for the glass fiber winding and unwinding operations for which they are used. In general, it can be said that such tubes are required to have a relatively smooth peripheral surface to permit the glass fibers to be readily unwound from the tube and at the same time this peripheral surface should be sufi'iciently rough so that satisfactory winding of the fibers on the tube may be accomplished. In addition, these tubes should also be of light weight to avoid deformation by centrifugal force which at the speeds referred to above is of a substantial magnitude. Furthermore, these forming tubes should be highly resistant to compression by the fibers wound tightly on the tube so that the tube maintains its shape after removal from the spindle and the tubes should have sufficient flexibility and elasticity to permit their ready removal from the wound package of glass fibers when the tube is to be reused.

Two commonly employed materials in use today for making such forming tubes are plain paper or paperboard and plastic such as polyethylene both of which have objectionable features. Although a forming tube composed solely of ordinary paperboard generally performs satisfactorily the first time it is used, its inherent lack of strength and lack of flexibility causes it to deteriorate rapidly when reused. It is thought that the rapid deterioration of such paper forming tubes occurs primarily as a result of the breaking of the cellulosic fibers in the tube resulting from the bending and folding to which such paper tubes are subjected. Therefore, forming tubes of fibrous material such as paper or paperboard are generally discarded after a few uses or even after a single use adding considerably to the manufacturing costs of such glass fibers even though the initial cost of such paper tubes is low. Forming tubes of plastic have also been used with some success but the severe stresses to which plastic forming tubes are subjected frequently causes plastic tubes to disintegrate or explode during use primarily as a result of centrifugal force not only creating a hazard but, as a result of the high initial cost of such plastic tubes, adding considerably to manufacturing costs.

Accordingly, a primary object of this invention is to provide a new and novel non-rigid forming tube having a novel surface for use in the winding of glass filaments or fibers.

Another object of this invention is to provide a new and novel non-rigid forming tube for winding glass fibers which utilizes a combination of two types of fibrous material which cooperate to provide high strength and flexibility so as to permit the forming tube to be used repeatedly with a minimum of wear.

A further object of this invention is to provide a new and novel non-rigid forming tube for winding glass fibers which utilizes readily available, inexpensive materials, which may be easily manufactured on conventional spiral tube winding apparatus and which contains a highly suitable winding surface for glass fibers.

Still another object of this invention is to provide a new and novel method of making a non-rigid forming tube for glass fibers and for providing a winding surface on the forming tube which is highly suitable for the winding of glass fibers.

Other objects and advantages of the invention will become apparent from the following description taken in connection with the accompanying drawing.

In general, the objects of this invention and other related objects are accomplished by spirally winding at least one strip of fibrous material such as paper into a paper tube. A strip of non-woven textile material impregnated with a suitable resin is then spirally wound over the wound paper tube during the winding of the paper tube. A ply of smooth, slick release material is then spirally wound in overlying relationship with the resin impregnated non-woven material after which the resin is permitted to cure. The resin in the ply of non-woven textile material adhesively secures the non-woven material to the underlying paper tube. When the resin has cured, the release material is unwound and discarded. The resulting forming tube comprises at least one inner spirally wound paper ply and an outer ply of resin impregnated nonwoven textile material having a hard, uniformly smooth, slick surface this surface having been impressed on the forming tube outer surface by the release material. The forming tube is flexible to permit it to be collapsed longitudinally for removal of the tube from a package of glass fibers wound thereon.

The novel features which are believed to be characteristic of the invention are set forth with particularity in the appended claim. The invention itself, however, both as to its organization and method of operation may be best understood by reference to the following description taken in conjunction with the accompanying drawing in which:

FIGURE 1 is a diagrammatic illustration of a tube winding apparatus for winding the forming tube of the invention;

FIGURE 2 is a sectional view taken substantially along line 22 of FIGURE 1 in the direction of the arrows;

FIGURE 3 is an enlarged isometric view of the tube of the invention as wound with the apparatus of FIGURE 1;

FIGURE 4 is an enlarged sectional view taken substantially along line 44 of FIGURE 3 in the direction of the arrows; and

FIGURE 5 is a sectional view similar to FIGURE 4 of the forming tube of the invention.

Referring now to the drawing and to FIGURE 1 in particular, there is shown diagrammatically a typical spiral tube winding apparatus by means of which the winding of the forming tube of the invention is carried out. As previously stated, the forming tube of the invention, which is shown in section and designated generally by the numeral 11 in FIGURE 5, is of the type which is particularly suitable for use in the winding of freshly spun glass filaments or fibers drawn from the spinneret of a glass furnace. However, the tube 11 of the invention may also be employed in other glass fiber manufacturing operations involving glass fiber winding and take-off procedures.

As generally illustrative of the novel method of winding the forming tube 11 of the invention, the conventional spiral tube winding apparatus of FIGURE 1 is designated generally by the numeral 12. In FIGURE 1, the spiral tube winding apparatus 12 is shown carrying out a winding operation by means of which a continuous tube T advanced in the direction of the arrow I is produced. The tube T is cut into suitable lengths to form the forming tube 11 of the invention as will be explained hereinafter.

As is well known, the spiral tube winding apparatus 12 comprises a frame 13, a stationary mandrel 14 supported on the frame, a fiexible endless belt 16 extending around a pair of pulleys 17 at least one of which is driven for rotating and advancing the tube T as it is formed and a cutoff device 18 for cutting the continuously wound tube T into uniform sections of a selected length.

In the winding of the continuous tube T, at least one strip 21 of fibrous material or paper unwound from a supply roll 22 is first wound on the tube making mandrel 14. Preferably two such paper strips are employed and accordingly a second paper strip 23 unwound from a supply roll 24 is wound in overlying staggered relationship with and at the same angle as strip 21 from the opposite side of the mandrel 14 as shown in FIGURE 1. The angle at which the paper strips 21, 23 are wound onto the mandrel 14 is preferably between 35 and 50 degrees relative to the longitudinal axis of the mandrel 14 and, in the illustrated embodiment, the strips 21, 23 are wound at an angle of approximately 40 degrees.

In order to adhere the paper strips 21, 22 together in the spirally Wound relationship, the paper strips 23 are advanced in contact with an applicator roll 26 suitably supported for rotation in a receptacle 27 containing a suitable adhesive in the Well-known manner. Thus, as the applicator roll 26 is rotated, it applies adhesive to the underside of the strip 23 and contact between the strip 23 and the applicator roll 26 is maintained by advancing the strip 23 under guide rollers 28, 29 also suitably supported for rotation on the receptacle 27.

In this manner, the two paper strips 21, 23, spirally wound with adhesive therebetween form a two ply paper tube 31 which is advanced under the belt 16 in the direction of the arrow I. The paper strips 21, 23 are preferably each wound with the edges of adjacent convolutions in an abutting relationship. Tube 31 therefore contains a spiral butt seam 23a as shown best in FIGURE 3.

As the tube 31 advances along the mandrel 14 down from the belt 16, a spirally wound outer ply 32 of nonwoven textile material which is impregnated with a suitable resin is Wound in overlying relationship with the Wound paper ply 23 of the wound paper tube 31. Strip 32 may be any suitable non-Woven textile material which is readily available commercially and which is formed from either natural or synthetic fibers in the well-known manner. As is well known, such non-woven textile material has many of the characteristics of paper except that it is formed from textile fibers such as rayon, cotton, polyester, etc.

The strip 32 is unwound from a supply roll 33 and is impregnated with a suitable resinous material by advanc ing the strip 32 through a receptacle 34 containing an impregnating resin bath 36 as shown in FIGURE 2. Preferably, the resinous material 36 is an acrylic resin which is provided in the form of an aqueous emulsion. The curing of this resinous material 36 may therefore be accomplished by the evaporation of the water vehicle from the acrylic resin and water mixture. Guide rollers 37-40 are suitably positioned as shown in FIGURE 2 adjacent the receptacle 34 so that the strip 32 is immersed in the resinous emulsion bath 36 and subsequently removed for winding on the paper tube 31. Preferably the impregnated strip 32 is wound with the edges of adjacent convolutions in overlapping relationship as shown best in FIGURE 3 which form an outer spiral seam 32a.

In order to provide a hard, uniformly smooth, slick surface on the impregnated non-woven ply 32 after the resin is cured, a wrapping ply 42 of smooth, slick release material such as polyethylene. Mylar or the like is unwound from a supply roll 43 and spirally wrapped as shown in FIGURES 1, 3 in overlying relationship with the impregnated non-woven ply 32. The ply 42 is preferably wrapped with the edges of adjacent convolutions in overlapping relationship as shown to form an outer spiral seam 42a completely covering the underlying resin impregnated ply 32. With the use of release material for the ply 42, it does not adhere to the resinous material with which the non-woven ply 32 is impregnated, and ply 42 is tightly wound in the spiral winding operation of FIGURE 1 with the underlying ply 32 to form the tube T. The tight engagement of wrapping ply 42 with the impregnated non-woven ply 32 not only confines the resin within ply 32 but produces a substantially complete engagement between the surfaces of the two plies.

As the continuously formed tube T moves in the direction of the arrow I, it enters the cutoff device 18 in which it is cut into uniform sections which are removed for curing. Preferably these tube sections are formed approximately eight feet in length and each comprise a four ply spirally wound structure as is shown in section in FIG- URE 4. The curing of the sections severed from the tube T is then carried out so that the water vehicle in the resinwater mixture in the tube outer ply 32 will be evaporated and the resin with which the tube T is impregnated will be set permanently within the tube. Using an aqueous acrylic mixture for impregnation of the tube ply 32 permits the curing to be accomplished under normal room temperatures over a relatively short period of time. However, if it is desired to shorten the curing by the application of heat, means such as an oven can be utilized.

After curing, the wrapping ply 42 of release material is then unwound from each cured tube section and discarded. After removal of the wrapping ply 42, it will be noted that the outer ply 42 of release material has compressed and smoothed the impregnated underlying ply 32 of non-woven material so as to provide a hard, relatively smooth, irregularly slick outer surface on ply 32 having randomly dispersed slick areas throughout substantially all of the surface. Dispersed among the slick areas, which in effect are a reproduction of the slick surface of the wrapping ply 42, are a few relatively uneven surface portions but far less in number than the slick areas so that the entire surface of the tube is one having a smooth, slick appearance and feel. The cured tube sec tions are then cut into a plurality of short lengths, preferably lengths of approximately eight inches, to provide forming tubes 11 of a length suitable for use in a glass fiber winding and unwinding operation.

It can be seen that there has been provided with the novel construction of the invention a forming tube for winding glass fibers which utilizes plies of non-woven textile material and paper spirally wound together in a manner such that the tube is extremely strong and at the same time suitably flexible to permit repeated use without wear and ease of removal from the wound package of glass fibers. At the same time, the forming tube of the invention is provided with a winding surface which is hard and uniformly smooth substantially throughout to provide a unique winding surface for glass fibers. This unique and novel winding surface is produced by a novel method utilizing smooth release material such as Mylar, polyethylene and the like which is wrapped on the resin impregnated ply of non-woven material while in the uncured condition so that the smooth, slick surface of the release material is impressed on the outer ply of nonwoven textile material after the resin is cured.

We claim:

1. A non-rigid forming tube for glass fibers comprising, in combination, at least one spirally wound inner ply of fibrous material and a spirally wound outer ply of resin impregnated, non-woven textile material having a hard, uniformly smooth, slick outer surface for the winding of glass fibers, said ply of non-woven textile material being impregnated throughout with said resin and adhesively secured to said inner ply with said resin, said ply of fibrous material and ply of non-woven textile material having a thickness and composition to permit said tube to be collapsed longitudinally for removal of the tube from a package of glass fibers wound thereon.

References Cited UNITED STATES PATENTS 3,226,799 1/1966 Grodberg et al. 29-120 2,760,549 8/1956 Nash et a1 156188 XR 2,751,936 6/1956 Dunlap et al. 138154 XR 2,723,705 11/1955 Collins 156188 XR 2,623,445 12/1952 Robinson 9394 2,129,478 9/1931 Rohm 2602 EARL M. BERGERT, Primary Examiner.

D. J. FRITSCH, Assistant Examiner.

US. Cl. X.R. l56188, 195 

